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added circle-line intersection

This commit is contained in:
Nico Pietroni 2007-05-08 12:11:58 +00:00
parent 5dd620e4e4
commit 43958eea39
1 changed files with 42 additions and 0 deletions
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42
vcg/space/intersection2.h
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@ -23,6 +23,8 @@
/****************************************************************************
History
$Log: not supported by cvs2svn $
****************************************************************************/
@ -208,6 +210,46 @@ template<class SCALAR_TYPE>
return((Convex(p,p0,p1))&&(Convex(p,p1,p2))&&(Convex(p,p2,p0)));
//return((Convex(p,p0,p1))&&(Convex(p,p1,p2))&&(Convex(p,p2,p0)));
}
//intersection between a circle and a line
template<class SCALAR_TYPE>
inline bool CircleLineIntersection(const vcg::Line2<SCALAR_TYPE> & line,
const vcg::Point2<ScalarType> &center,
const ScalarType &radius,
vcg::Point2<ScalarType> &p0,
vcg::Point2<ScalarType> &p1)
{
///translate with origin on the center
ScalarType x1,x2,y1,y2;
x1=p.X()-center.X();
y1=p.Y()-center.Y();
x2=x1+line.Direction.X();
y2=y1+line.Direction.Y();
ScalarType dx,dy,dr,D,delta,sign;
dx=x2-x1;
dy=y2-y1;
dr=sqrt(dx*dx+dy*dy);
D=x1*y2-x2*y1;
delta=radius*radius*dr*dr-D*D;
if (dy>=0)
sign=1;
else
sign=-1;
if (delta<0.000001)
return false;///no intersection
else
{
p0.X()=(D*dy+sign*dx*sqrt(delta))/dr*dr;
p0.Y()=(-D*dx+fabs(dy)*sqrt(delta))/dr*dr;
p1.X()=(D*dy-sign*dx*sqrt(delta))/dr*dr;
p1.Y()=(-D*dx-fabs(dy)*sqrt(delta))/dr*dr;
p0+=center;
p1+=center;
return true;
}
}
/*@}*/
} // end namespace
#endif